#9 Add separate colors to attribute names and values

[Jonathan Keeling]

This patch declares new markup-types, attnm and attval,
and marks up attribute names (the region parsed by
sgml-parse-nametoken), and values (the region parsed by
sgml-parse-attribute-value-specification) with these types.
The point is saved before and after parsing element lists,
and deliminators are marked as start-tag.

Patch provided for version 1.2.5

[Jonathan Keeling]

Patch to psgml-parse.el